There is a need and desire to incorporate physical features into products handled by visually impaired people so that they can discern certain characteristics relating to such products. For example, it is important that visually impaired people be able to distinguish and use products such as security documents, in particular, different denominations of banknotes. For this purpose, currency-issuing national banks are implementing various features in the production of banknotes. Examples include varying the size of banknotes and printing tactile marks, such as Braille markings or deep intaglio patterns and non-intaglio, deep embossments on the banknotes which may be discerned by touch (i.e. by the user feeling the document in the area of such marks, patterns and embossments). However, in order to be effective and acceptable for use in the security printing industry, the composition to be used to print such tactile markings onto a banknote substrate must produce markings which have a durable tactility and integrity. The compositions used to date for this purpose have been found to lack durability in one or both of tactility and integrity, because the tactile markings they produce either too quickly become flattened over a period of use so as to become less tactile or too easily become broken off or torn from the substrate on which they were printed, or both.
Therefore, there is a need for an improved method and composition for industrial printing of tactile markings onto substrates, particularly banknotes, which are required to remain intact throughout a given circulation life.